The invention relates to a method and a device for drying materials (1) in a holding vessel (2). Air (20, 37) is guided or pumped out of the holding vessel (2). The drying process is monitored and/or influenced by measuring the relative air humidity ( phi ) of the air (37) that is guided or pumped out of the holding vessel (2) using a measuring device (7) for measuring the relative air humidity, in order to improve the control and/or regulation of the drying process and especially in order to determine the completion of the drying process more accurately. The measured value that is acquired can be used to determine the time at which the drying process is complete and to monitor and optimise, i.e. especially accelerate the drying process, by regulating further parameters thereof. The inventive method and device are also particularly suitable for drying materials or samples with an unknown water content or with an unknown composition.